You can change your Windows server's password using Remote Desktop Connection.

To Change Your Password on a Windows Server

1. Launch Remote Desktop Connection.
2. Enter the IP address for your server. You can find your IP address in your Dedicated/VPS Control Panel.
3. Enter your user name and password:

   user Name

   Use either "Administrator" or the User ID you defined when you set up your account.

   Password

   As defined during account setup.

4. From the Start menu on your Windows server, select Control Panel > Administrative Tools > Computer Management.
5. In the Computer Management Window, select the Users.
6. Right-click on the account you want to modify and select Set Password.
7. Read the warning message and click Proceed.
8. Enter your new password and then enter it again to confirm. Click OK to finish making the change.

You can change your Linux server's password using SSH.

To Change Your Password on a Linux Server

1. Connect to your server via SSH (more info).
2. At the command line type passwd and the name of the account you want to change. For example:
   [username@ip_address]# passwd user_you_want_to_change
   Changing password for user user_you_want_to_change.
   (current) UNIX password: ********
   New UNIX password: ********
   Retype new UNIX password: ********
   passwd: all authentication tokens updated successfully.
   

If you change the root password, Linux will warn you if your password is not considered a strong password, but still make the change.